Calculator using PHP and Css 3 ,html 5

Calculator Using PHP...

<title>Calculator</title>
<style>
span{
background-color: lightgreen;
border: 2px solid black;
textcolor: red;
}
div input{
    background-color: lightgrey;
    width: 320px;
    padding: 5px;
    border: 1px solid navy;
    margin: 25px;
}
div button{
    background-color: #FFFFF0;
    width: 360px;
    height: 40px;
    padding: 5px;
    border: 2px solid green;
 
}
div td{
    background-color:#FFEBFF;
    width: 200px;
    height: 10px;
    padding: 5px;
    border: 2px solid navy;
    }
div th{
    background-color: #FFD6D6;
    width: 200px;
    height: 10px;
    padding: 5px;
    border: 2px solid navy;
 
}
 p{
    background-color: #FFF5FF;
    width: 420px;
    height: 25px;
    padding: 5px;
    border: 3px solid black;

}
</style>


<form action=" " method="POST">
<div><table border=2"><tr><th color="red" width="59">
Value 1:<br><input type="text" name="a" ></th><th>
Value 2:<br><input type="text" name="b" ></th></tr><tr><td>
<input type="radio" name="s" value="+">Additon<br></td><td>
<input type="radio" name="s" value="-">Subtraction<br></td></tr><tr><td>
<input type="radio" name="s" value="*">Multiplication<br></td><td>
<input type="radio" name="s" value="/">Division<br></td></tr><tr><td>
<input type="radio" name="s" value="sin">Sin<br></td><td>
<input type="radio" name="s" value="cos">Cos<br></td></tr><tr><td>
<input type="radio" name="s" value="tan">Tan<br></td><td>
<input type="radio" name="s" value="decbin">Decimal to Binary<br></td></tr><tr><td>
<input type="radio" name="s" value="bindec">Binary to Decimal<br></td><td>
<input type="radio" name="s" value="dechex">Decimal to Hexa<br></td></tr><tr><td>
<input type="radio" name="s" value="hexdec">Hexa to Decimal<br></td><td>

</div>
<button value="Submit" name="submit" type="Submit">Submit</button></td></tr>
</form>

<tr>
<?php
$ans=0;
$a=$_POST['a'];
$b=$_POST['b'];
$q=$_POST['s'];
switch($q)
{
case "+":
$ans=$a+$b;
echo "Sum= ".$ans;
break;
case "-":
$sub=$a-$b;
echo "Sub= ".$sub;
break;
case "*":
$mul=$a*$b;
echo "Mul= ".$mul;
break;
case "/":
$div=$a / $b;
echo "DIV= ".$div;
break;
case cos:
 $ans = cos($a);
  break;
  case sin:
 $ans = sin($a);
  break;
  case tan:
 $ans = tan($a);
  break;
  case decbin:
 $ans = decbin($a);
  break;
  case bindec:
 $ans = bindec($a);
  break;
  case dechex:
 $ans = dechex($a);
  break;
  case hexdec:
 $ans = hexdec($a);
  break;
  case deg2rad:
 $and = deg2rad($a);
  break;
  case rad2deg:
 $ans = rad2deg($a);
  break;
}
echo "<p><i><b> Answer =<b><i> ".$ans."</p>";
//echo "<input type=/"text/" value='".$ans."'>";


?></tr></table>

<center><span>Copyright @ Programming SeekerzzZ </span></center>

Value 1:	Value 2:
Additon	Subtraction
Multiplication	Division
Sin	Cos
Tan	Decimal to Binary
Binary to Decimal	Decimal to Hexa
Hexa to Decimal

Answer = ".$ans.""; ?>
Copyright @ Programming SeekerzzZ